Per Major League rules, if you pinch hit for any player, that player cannot return to the game in any position.
In most youth league rules, such as USSSA, Pony, etc., starters can re-enter a game for the substitute that replaced them, but a pitcher, once removed as a pitcher, cannot pitch again in the same game.
The starting pitcher.
Yes. But he has to face at least 1 batter.
The pitcher is credited with a fraction that represents how many outs there were in the inning when they are relieved. If the pitcher is relieved is one out, they are credited woth 1/3 (one-third) of an inning. If the pitcher is relieved with two outs, they are credited with 2/3 (two-thirds) of an inning. A pitcher who starts the game and is relieved with one out in the seventh inning is credited with 6 1/3 innings pitched ... if relieved with two outs in the seventh inning is credited with 6 2/3 innings pitched. ... if relieved with no outs in the seventh inning is credited with 6 innings pitched.
Yes. In MLB, a player who starts the game as the DH may be inserted into the game as a fielder. If this is done, the team loses the ability to use a DH and the pitcher must be inserted into the batting lineup.
With a pitcher pitching to a batter who is trying to hit the ball and it starts with either him getting out, getting a hit, or getting walked.
The expected average number of starts for a pitcher, barring injuries, is 33.
Nolan Ryan with 773 starts.
Shane Victorino, Center Fielder for the Philadelphia Phillies.
Livan Hernandez with 332 starts.
For example, if a pitcher comes in to start the seventh inning, gives up two base hits and is replaced without recording an out, the box score will show he pitched 0 innings. At the bottom of the box score it will have a statement "<name of pitcher> pitched to two batters in the seventh inning'. Sometimes you hear broadcasters refer to it as 'plus'. Say the starter is replaced after giving up a base hit in the seventh inning but before recording any outs. You might hear the broadcaster say "<name of pitcher> went six plus innings today".
Randy Johnson - The big Unit The nicknames of a baseball pitcher are as follows; hurler, fireballer ( a good fastball pitcher), starter ( usually only starts games) ace ( your best starting pitcher), reliever ( takes over in later innings for a starter), setup man ( 8th inning guy who sets up for the 9th inning) closer ( comes in usually only for the 9th inning to close out a game) middle reliever, southpaw ( a left handed pitcher), lefty, righty, some one who is "on the bump" is a pitcher and it refers to the pitcher's mound, Knuckleballer ( a pitcher who usually only throws a slow, hard to hit knuckleball), specialist ( usually refers to a left handed pitcher that only pitches to left handed batters). That's all I can think of right now.